Magnetic latch



Nov. 12, 1957 J. L. KNIGHT MAGNETIC LATCH Filed Oct. 4, 1955 FIGJ FIG. 2

INVENTOR. JAMES L. KNGHT BY Hs ATTORNEY MAGNETIC LATCH James L. Knight, Louisville, Ky., assignor to General Electric Company, a co'poration of New York Application October 4, 1955, SerialNo. 538,503

4 Clams. (Cl. 292-251.5)'

My nvention relates to magnetic latches and more particularly to magnetic latches for use with cabinets, such as refrigerator cabinets, having relatively heavy doors which are sealed to the cabinets when in the closed position.

It is an object of my invention to provide a new and improved magnetic latch for such use.

It is another object of my invention to provide a new and improved magnetic refrigerator latch in which the magnet is adapted to be disposed within the scaling gasket of the refrigerator and is so mounted on the member carrying the gasket that it may tilt'within the gasket to correct for misalignment between the door and the cabinet.

A further object of my invention is to provide a magnetic latch of this type, in'which the door flange on one of the cabinet anddoor members serves as a means for mounting the magnet within the gasket and the door fiange on the opposite of the members serves as the magnetc armature.

Another object of my invention is to provide a'magnetic latch` of the latter type including means for preventing fiux saturation in the fiange acting as an armature and means for preventing damage to the outer surface of the flange by the magnet.

In carrying out my nvention, I provide a magnetic latch particularly adapted for use in cabinets, such as refrgerator cabinets, wherein the door member and the cabinet member are sealed together by a compressible sealing gasket when the door is in its closed position. The'latch is mounted on one of the door and cabinet members and it includes an elongated magnet and a rigid backing element. The hacking element is` disposed behind the magnet and is fixedly attachedto the member mounting the latch. Between the magnet and the hacking element there is positioned a spacer which spaces the magnet from the hacking element and provides for tilting of the magnetrelative to the hacking element and the member mounting it. For holding the magnet in position against the spacer, the latch includes a strap which extends through the hacking element and around the magnet. This strap is biased inwardly by means of a spring disposed between it and the hacking element, and it thereby pullsthe magnet in against the spacer. With the magnet resiliently engaged in this manner with the spacer, it may tilt on the spacerto correct for misalignment occurring between the door member and the cabinet member.

The novel features which I believe to be characteristic of my invention are set forth with particularly in the appended claims. My invention, however, both as to its organization and method of operation, may be best understood by reference to the following description taken n conjunction with the accompanying drawings in which:

Fig. lis a fragmentary horizontal sectional view of a refrigerator cabinet, showing a preferred embodiment of my invention as applied to such a cabinet;

Fig. 2 isa fragmentary sectional view taken on the line 2-2 of Fig. l; and

nite States Patents Office Patented Nov. 12, 1957 Fig. 3 is a fragmentary sectional view similar to Fig. 2 showing an alternate embodiment of my invention.

Referring now to Fig. 1, I have shown therein a preferred embodiment of my new and improved magnetic latch as applied to a household refrigerator 1. The

refrigerator 1 includes a cabinet member 2 having spaced apart inner and outer walls 3 and 4. These walls in my preferred embodiment are both formed of sheet steel. The space between the walls 3 and 4 is filled with suitable heat insulating material 5 and the walls are joined together in the region of the access opening to the refrigerator by an insulating breaker strip 6. The refrigerator 1 further includes a door 7 which is supported from the cabinet 2 by means of suitable hinges (not shown). The door is adapted to Swing on these hinges so as to open and close the access opening to the refrigerator. The door includes inner and outer walls 8 and 9 and the space between the walls is filled with heat insulating material 19. But since the inner wall or liner 8 is formed of a suitable heat insulating, plastic material, no breaker strip is needed between the door walls.

Both the outer shell 4 of the cabinet and the outer wall 9 of the door include an inwardly extending fiange in the region of the door or access opening to the refrigerator. Specifically, the cabinet shell 4 includes an inwardly extending flange 11 and the door shell 9 includes an inwardly extending flange 12. These flanges 11 and 12 in my preferred embodiment extend all the way around the periphery of the door opening. In order to seal together the door and the cabinet when the door is closed, a compressible gasket 13 is mounted on one of these flanges so` that it engages and is compressed by the other of the fianges when the door is closed. In my preferred embodiment, the gasket 13 is mounted hy means of the fiange 12 so that it engages the flange 11 when the door is closed; The means whereby the gasket 13 is attached to the flange 12 are not shown since it will be understood that' any suitable means may be used. In my preferred embodiment a groove 14 provided in the door line' 3 may be utilized as a portion of the mounting means.

In order to latch the door 7 in the closed position, I have applied to the refrigerator 1 a preferred embodiment of my new and improved magnetic latch. In the refrigerator i this latch is mounted at approximately the middle of the side of the door opposite from the hinges. However, a different positioning of the latch can be used, and, in fact, with very large doors two of these latches can be utilized to provide a proper latching action. In the latter case, for best results, one latch is positioned at the top' of the side cpposite the hinges and the other latch is positioned at the bottom of that side.

The latch includes an elongated magnet 15 which is disposed within the gasket 13.

and it may. be formed of any suitable magnetic material, as for example, the material commercially known as' Alnico, or the like. For the particular magnet dimensions shown, i. e. for the particular ratio of magnet lengthto cross section, Alnico V would be the preferable material, but by adjusting the magnet dimensions other material could also be used with good results.

The magnet 15 produces a magnetic flux which links Being disposed within* the gasket, the magnet 15 is of course concealed from' The legs 17 guide the a suitable armature on the cabinet 2 so as forceahly to hold the door 7 in a closed position. In other words, the magnet 15 by its magnetic attraction to the armature holds the door inthe closed position. In my preferred embodiment the armature comprses the flange 11 of the door shell 4. The flange 11 being formed of steel is perfectly suitable for use as an armature. By its use the need for additional armature parts is obviated, and in addition there need he no holes in the flange or parte jutting upwardly therefrom so as to detract from the appearance of the cabinet.

In order to prevent magnetic saturation of the flange 11 and thereby ohtain the best utilzation of the magnetic fluX from the magnet 15, a small steel block 18 is prefer ahly positioned behind ti e flange in the region of the magnet 15. This steel block 18 provides an additional flux path and thereby prevents the flange from being saturated. Saturation of the flange 11 is of course undesirable in that it limits the attractive force supplied by the magnet below the highest force possible. It will be understood, however, that the latch will operate without the addition of a block such as the block 13, although the best results are Secured from its use. In order to protect the flange il, a thin stainless steel trim piece 19 may he positioned over it in the region of the magnet. The trim piece 19 is desirable since otherwise the paint on the flange :ll might tend to flake oli due to the contact of the magnet with the flange. It will be understood though that the trim piece 19 is provided only in the region of the magnet and does not extend over the remaining length of the flange. i

By my invention, the magnet 15 is so mounted within the gasket 13 that it may tilt or rock to correct for misalignment between the door 7 and the cabinet 2. Normally, as shown in Fig. 2, the magnet 15 extends substantially parallel to the flange 12 and the face of the door 7. However, if there is a slight misalignment between the face of the door 7 and the face of the cabinet 2, the magnet by tilting or rocking may line up with the cabinet 2 so as to make a proper contact therewith By so doing it provides the greatest force for holding the door closed.

In my novel mounting of the magnet, which provides this tilting action, the flange 12 of the door serves as a rigid hacking element for the magnet and the remaining members of the mounting means are supported or held from the flange. The magnet 15 is spaced from the flange or hacking element 12 by means of a suitable spacing element or block 20. The block or spacer 20 in the embodiment of Fig. 2 comprises a piece of resilient non-magnetic material such as sponge rubber. The spacer 20, of course, holds the magnet 15 away from the flange 12 so that no appreciable amount of flux from the magnet links the flange or hacking element 12. Further, the spacer 20 by its resilience allows the magnet to tilt or rock so as to correct for misalignment between the door and the cabinet. in other words, the spacer 20 by its deformation allows the magnet to change its position slightly so that its principal plane may correspond with that of the cabinet flange 11. Due to its resiliency, the spacer 20 also is efiective to take up some of the impact as the magnet strikes the cabinet on closing of the door.

For holding the magnet 15 against the spacing block 20, I have provided a generally U-shaped strap 21. The strap 21 extends through an aperture 22 in the flange or hacking element 12 and fits around the center portion of the magnet 15. Specifically, the bight 23 of the strap refrigerator gaskets, a section of the rear portion of the tube is cut away in the region of the latch so as to allow for the insertion of the magnet 15, the block 20 and the strap 21.

The strap 21 holds the magnet 15 against the spacing -block Zt) in such a manner that the magnet can rock or tilt on the block, and fo'r that purpose the strap 21 is itself not rigidly attached to the flange or hacking element 12. However, the strap is arranged so that it is free to move within the aperture'22 in the flange. To hoid the magnet against the spacng block the strap 21 is biased inwardly by means of a suitable spring 25 which engages both it and the flange 12. Specifically, the strap is provided with a pin 26 which extends hetween its legs at the inner ends thereof, and the spring 25 is disposed between this pin and the inner side of the flange 12. The spring is compressed by its engagement between the pin and the flange and thereby is efiective to hias the pin and the strap inwardly. This holds the magnet 15 firmly hut resiliently against the block 2%. The spring 25 preferahly comprises a howed leaf spring whose center portion engages the pin 26 and whose ends engage the flange 12; and in my preferred embodiment a depression 27 is provided in the center portion of the leaf spring 25 so as to prevent the pin 26 from jumping off the spring during use. In this manner, the magnet 15 is resiliently held against the block 20 so that itmay rock or tilt through the deformation of the block, and thereby correct for misalignment between the door and the cabinet.

Referring now to Fig. 3, I have shown therein an alternate emhodiment of my invention. This emhodiment is generally similar to the embodiment of Figs. 1 and 2, and the elements in Fig. 3 which are identical to those in Figs. 1 and 2 are indicated by the same reference numbers., In this embodiment also, the latch is mounted on the door 7 and includes a generally elongated U-shaped magnet 15 which is positioned within the sealing gasket 13. This magnet 15 provides a flux which links the flange 11 of the cabinet 2 so as to hold the door in the closed position. A steel block 18 is nounted behind the flange 11 in the region of the latch to provide an additionai flux path for preventing magnetc saturation of the flange; and a stainless steel strip 19 is disposed over the outer face of the flange to protect it during use. a

The magnet 15 is mounted by means of the door flange or hacking element 12 which supports the gasket 13. The magnet 15 is however mounted so that it may rock or tilt relative to the face of the door thereby to correct for misalignment between the cabinet and the door. In order to provide this rocking or tilting elfect, a fulcrum type spacer 30 is disposed between the magnet 15 and the door flange 12. This fulcrum type spacer is formed of any suitable non-magnetic material, for example non-magnetic plastic material, and is generally V-shaped in cross section. It thus provides a pivot or knifeedge 31 around which the magnet may rock or tilt so as to correct for misalignment. The spacer, of course, also physically spaces the magnet away from the flange 12 so that there is no appreciahle amount of flux leakage through the flange.

The magnet 15 is resiliently held against the knife edge 31 by means of a generally U-shaped strap 21 which extends around its central portion. The bight 23 of the strap is preferably fitted within a groove 24 in the central portion of the magnet. The strap 21 is not attached to the flange or hacking element 12 but rather is free to move in the aperture 22 of the flange. To hold the magnet against the spacing element, the strap is hiased inwardly by means of a spring 25. The spring 25 comprses a bowed leaf spring which engages the flange 12 at its ends and the strap '21 in its center portion. Specifically, a groove 27 in its center portion engages a pin 26 running between the ends of the strap. The spring thus normally pulls the strap inwardly so as resiliently to hold the magnet against the spacer 36. This spring mounting permits the magnet to tilt or rock on the fulcrum or knife edge 31 of the spacer so as to correct for misalignment between the cabinet and the door.

While in accordance with the patent statutes I have shown What at present are considered to he the preferred embodiments of my invention, it will be obvious to those skilled in the art that various changes and modifications may he made therein without departng from my inven tion, and I, therefore, aim in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of my invention.

What I claim as new and desre to secure by Letters Patent of the United States is:

1. A magnetic latch for holding a door member in a closed position relative to a cabinet member comprising an elongated magnet, a rigid hacking element disposed behind said magnet and arranged to be attached to one of said members, a spacer positioned between said magnet and said hacking element to provide for tlting of said magnet relative to said hacking element and said one member, a strap adapted to extend through said hacking element for holding said magnet, and a spring engaging said strap and said hacking element for biasing said strap inwardly to pull said magnet against said spacer whereby said magnet may tilt on said spacer to correct for misalignment between said door member and said cabinet member.

2. A magnetic latch for holding a door member in a closed position relative to a cabinet member comprising an elongated magnet, a rigid hacking element disposed behind said magnet and attached to one of said members, a resilent spacing block disposed between said magnet and said hacking element for normally positioning said magnet parallel to the face of said one member, said block being resiliently deformable to provide for tilting of said magnet relative to said hacking member and said face whereby said magnet may tilt to correct for misalignment between said cabinet and door members, a U-shaped strap extending through said hacking element and around said magnet for holding said magnet, and a spring engaging said strap and said hacking element for biasing said strap inwardly to pull said magnet against said block.

3. A magnetic latch for holding a door member in a closed position relative to a cabinet member comprising an elongated magnet, a rgid hacking element disposed behind said magnet and attached to one of said members, a fulcrurn element disposed between said magnet and said hacking element, said fulcrum element spacng said magnet from said hacking element and providing for tilting movement of said magnet relative to said hacking element and said one member whereby said magnet may tilt to correct for misalignment between said cabinet member and said door member, a U-shaped strap extending through said hacking element and around said magnet for holding said magnet, and a spring engaging said strap and said hacking element for biasing said strap inwardly to pull said magnet normally against said fulcrum element.

4. A magnetic latch for holding a door member in a closed position relative to a cabinet member wherein at least one of said members has an inwardly extending fiange, said magnetic latch comprising an elongated magnet adapted to be disposed in front of said flange, a spacer positioned between said magnet and said flange and providing for tilting of said magnet relative to said flange and the member mounting said fiange, a U-shaped strap adapted to extend through said ange and around said magnet for holding said magnet, and a spring for engaging said strap and said flange to bias said strap inwardly to pull said magnet resiliently against said spacer.

References Cited in the file of this patent UNITED STATES PATENTS 

